Electronic computer



Oct. l0, 1950 G. A. MoRroN ELECTRONIC COMPUTER 4 sheets-sheet 11 Filed Aug. 22, 1945 INVENTOR. A 62am: A. /VoRro/v l E @Ef/5 I irraefyiy Oct. l0, 1950 .-GQA. MoRToN ELECTRONIC COMPUTER 4 sheets-sheet 2 Filed Aug. 22, 1945 IIIA INVENTOR.

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Arrig/ e/viy Oct. l0, 1950 GA. MoRToN 2,525,077 ELECTRONIC COMPUTER Filed Aug. 22, 1945 v44 Sheets-Sheet 3 /ViIT/Vi PULSE' Pam? /fvPz/r' I I -sadV zieren/v N Rw me N., ma VM .e m.: ,w AA/ .M E 6 .w 6W

Oct. 10, 1950 G. A. MoRToN 2,525,077

ELECTRONIC COMPUTER y Filed Aug. 22, 1945 1 sheets-sheet 4 za 4a v INVENTOR.

iaeaf A. Makro/Y Patented Oct. 10, 1950 .l

ELECTRONIC COMPUTER George A. Morton, Princeton, -N. J.; assgnor to Radio Corporation of America., a corporation of Delaware Application August 22, 1945, Serial No. 612,035

The present application is a continuation-inpart of an application Serial No. 495,802, led July 21, 1943 which has become abandoned.

This invention relates to electronic computers such as are adapted to derive a value of a function of one or more Variables, and has for its principal object the provision of an improved computer and method of operation whereby such a function may be computed with an accuracy greater than the accuracy of particular circuit components by interpolating electronically between predetermined -values of each of the variables.

In one modication of the invention, such electronic interpolation is elected by means including a single cathode ray tube in which is provided for each of the variables involved in the computation (l) a screen provided with widely and accurately spaced conductors and (2) a screen provided with closely and less accurately spaced conductors. These coarse and fine screens are so mounted with respect to one another that any inaccuracies produced by irregular spacing of the conductors of the ne screen are periodically corrected by the more accurately spaced conductors of the coarse screen.

Means are provided for applying to the deflectors of the cathode ray tube pulses by which the cathode ray is moved by discrete steps between the conductors of the coarse screen or from one conductor to another of the ne screen.

There also is provided a higher order counter section and a lower order counter section which are so interconnected with the ine` and coarse screens and the source of ray deecting pulses that a count previously established in the coarse counter is reduced by one each time the ray crosses one of the conductors of the coarse screen. When the count of the higher order counter section is reduced to zero, the ray is caused to traversea number of the line screen conductors, in response to a number of pulses from an oscillator, determined by the count previously established in the ne counter section.

In moving step by step across the ne and coarse screens, the ray passes over the secondary electron emissive lines of a target from which pulses are delivered to establish in a separate counter a representation of a value of the function determined by the counts established in the higher and lower order counter sections as representative of a given value of the variable or variables.

Important objects are to provide an improved means for computing electronically a function of 14 Claims. (Cl. 235--61) one -or more Vvariables with an accuracy'exceed'- ing that inherent in some of the component ele"- ments of the computer; and to provide an improved means for interpolating electronically 4between Athe higher order values of the variables.

The invention will be better understood from the following description considered in connection with the accompanying drawings and its scope'is indicated by the appended claims. Referring to the drawings: y Figure 1 illustrates a computer constructed in accordance with the invention, n

Figure 2 illustrates a cathode ray tube target `electrode whichforms a part of the computer ofA Fig. 1, Y

' Figurev Sshows certain details of the counters which form a part of the computer of'Fig.-1,

g Figure 4 is a wiring diagram of the switches which lform a part vof the computer of Fig; 1, Figure 5 illustrates a modied form of the invention, andv Figure 6 shows the connections of the amplifiers which form apart of the computer ofl Fig. 5.

The electronic computerv of Fig. 1 includes a cathode ra-ytube II' which has a cathode I2; a control electrode I3, a screen velectrode I4, a pair of ray deflectors 2%);29, a ray deection control screen I8 anda target electrode 22,' A resistor I'I is connected in the circuit of the control elec#- trode I 3 and a resistor 49 is'connected in th'e circuit of the deection control screen I8. Voltages for operating the tube VII' are derived from a suitable source (not shown) through a voltage divider I6 which is grounded at its right-hand end. Voltage for deecting-the ray of the "tube II by discrete Asteps is applied tothe derlectors 2li-"29' from an oscillator 3| through a Shaper 45,` a switch i 46, a-diode 47 and a capacitor 48. `Atthe end-of its travel, the ray may be'returned to itsnrmal position at vthe left-hand side yofthe target'22by closing a reset switch 48 through which"lthe charge of the capacitor 48 isrremoved. f

The deflection control screen I8 includes a'plu-i` rality of ,accurately spaced conductors I8 which (l) are supported iny a suitable frame member I-8"; and (2) are struck by the cathode ray as it moves step by step in response to' the incremental volte" age applied to the deectors 2li-29'. Each time the ray strikes one of the conductors I8', a negative pulse is applied to a conductor 49'. `The number of deilection pulses required to move the ray of the tube II from one to another of the conductors I8r is of course dependent on (1) the voltage of such pulses (applied through diode 41)v and (2) the capacitance of the capacitor II8.'y Y

The path followed by the ray of the tube Il is controlled (1) by a coarse counter 21 which is set to determine how many of the conductors I8 are crossed by the ray and (2) by a ne counter 26 which is set to determine how many steps the ray takes after it has crossed enough of the conductors I8 to establish in a counter` 23 and an indicator 24 the value of the function corresponding to that part of the value of the variable set up in the counters 21.

A count representative of a given value of the variable X is established in the counters 26 and 21 by applying to a terminal 25 a number of negative pulses chosen to represent that particular value of the variable. The connections between the counters 26 and 21 are such that each time the counter 25 is lled, one negative pulse is delivered from the counter 26 to the counter 21. In general, any value of the variable-X will be represented by a higher order count established in the counter 21 and a lower order count established in the counter 26.

'Operation of the device of Fig. 1 is initiated by closing and opening of a switch i4V to apply a negative potential to the lead C of the switch 46. The detailsl of this switch are explained in connection with Fig. 4. It is so constituted that the application of a negative pulse to its lead C opens a path for the passage of pulses from the oscillator 3l and the Shaper 45 through the diode 41 to the capacitor 48. This capacitor is connected to the deflector 29 which has its potential raised as the chargel of the' capacitor is increased. As a result. the ray of the cathode ray device is moved from left to right across one after another of the conductors I8'.

The counters 26 and 21 are of a type which may be set to add or subtract the pulses applied to' their input terminals. Thev are disclosed and claimed in a copending application of Flory and Morton, Serial No. 464,293, which was led November 2, 1942 and is now Patent No. 2,462,275, and their various details are to be discussed in connection with Fig. 3 of the present application. When they are set tothe add position, al1 the negative pulses applied to the terminal 25 are added. When they are set to the subtract position, each negative pulse applied to the input circuit of either of them subtracts one from the count established in it.

The count established in the counter 21 is reduced bv negative pulses delivered from the screen I8 when the rav strikes one of the conductors I8'. When the counter 21 is restored to its no count condition. a negative pulse is delivered from it for closing a switch 46 so that pulses are delivered from the oscillator 3l through the Shaper 4R, tbe switches 45 and 46 and the conductor 4B for reducing the count of the counter 25. When the counter 26 is restored to its no count condition, a negative pulse is delivered from it for opening the switch 46. Under these conditions, the ray is positioned at some point, such as the point P, for example, and may be returned to its normal position at the left-hand edge of the target 22 by closing the switch 48'.

The normal position of the ray may be either at the left-hand edge or at the lower left corner of the target 22 depending on whether the desired function is that of a single variable or that of two variables. While the computer of Fig. 1 has been shown as arranged to derive the function of a single variable, it is obvious that its adaptation to the derivation of the function of more than one variable merely involves the provision of (l) a pair of vertical deilectors, (2) a deflection control screen having horizontal con-` ductors spaced similarly to the conductors I8 of the target I8, and (3) additional counters, additional switches, an additional diode, and an additional capacitor for controlling vertical deection ofthe ray in the same Way that its horlzontal deection is controlled. Such additional deflectors, deflection control screen and control means have been omitted from Fig. 1 to simplify an understanding of the invention. They are shown in Fig, 5 of the present application.

The target 22 may consist of a carbonized nickel plate having lines 44 of a silver magnesium compound suitable for producing secondary electron emission and delivering a pulse to the counter 23 each time the ray crosses one of these lines. If the secondary electron emission from these lines is greater than unity, the delivered pulse will be positive. If it is less than unity, the deliveredV pulse will be negative. How either a positive or a negative pulse may be utilized to establish a count representative of the desired value of the function is too well understood by those skilled in the art to require explanation.

The secondary electrons emitted from the lines 44 may be collected by a grounded coating 44 or even by the other electrodes of the tube I I since their effect on the potentialsof these electrodes is so small as to be'negligible.

The arrangement of the lines 44 is determined by the character of the desired function of the variablev or variables. For example, if a function of a single variable is to be derived, deflection of the ray is along only one axis and the lines are spaced from one another along this axis as determined by values derived from the usual function table. If a function of two variables is to be derived, the ray is deflected along one axis in accordance with the value of one of the variables and along another axis in accordance with the value of the other of the variables. In the case of two variables, the lines 44 are spaced and arranged in accordance with the Values derived from a function table so that the same number of lines are crossed bythe ray regardless of the path followed by the ray from its normal position to a given point on the target 22.

For the sake of simplicity, the lines 44 of the target 22 are shown as circular about the lower left-hand corner of the target. In this case, the derived function f(XY)=\/X2IY2. For other functions, the arrangement of the lines are different. In any case, the proper arrangement of the lines is readily determined from the function table values keeping in mind the fact that the contour of the lines must be such that the ray must not cross any line twice in Vits travel from its normal position to the point at which the desired value of the function is counted and indicated. In Fig. 2 is indicated by a horizontal line the path of the ray (l) for the case of'Fig. l and (2) by a line having inclined and horizontal parts in the path of the ray for the case of Fig. 5 in which the X and Y deflections are simultaneous and the value of X is somewhat greater than that of Y.

As indicated by Fig. 3, the counters 26 and 21 each include a 4plurality of trigger circuits IUI- I02, III-I I2, I2I-I22, I3I-I32, I4I-I42, IBI-|52, etc. Each of these trigger circuits includes a pair of triodes which have their anodes vand grids cross connected so that current is conducted by only one of the triodes at a time and is transferred from one of the triodes to the other in response to the application of a negative-pulse to the common anode terminal of the two triodes. Thus assuming the triode to be `conducting,

through transfer vtubes"|08, H4, |24, etc. for' subtraction of the pulses applied from the screen I8 Y Y (Fig. 1) to the conductorr49' and from the oscil lator 3| to the terminal 25. p A y y vSuch transfer of negative pulses through the current is transferred to the triodeY |02 in re- 5 sponse to the application of a negative pulse to transfer tubes is controlled by switchesSll and the terminals 25 and is transferred backto the SI02. lThus when the switch S|0| is in its left` triode |0| in response to the next successive hand closed'postion, the transfer tubes |06, ||5,r negative pulse applied to the terminals 25. `The |26, etc. are biased on by a battery |01 and ne'gaf same is true of all the otherltriggercircuits tive pulses are transmitted thro-ugh these tubes lli-H2, |2|-|22, |3|-|32, |4|.-|ll2,- |5|a|52, whenever the righthand -section of the related etc. K f ji i trigger circuit is rendered conductive. When the The trigger circuits of the differentr ordersfa're switch S|0| is in its righthand closed position, operated to a binary Zeroreprese'ntative' condi# however, the transfer tubes' |06, H5, |25, etc. are tion with current conduction- /in the triodes biased off and no negative pulses are transmit-v |0|-| l |-|2|-|3|'-|ll|-|5| etc. Aby closing ted through them. Similarly, the transfer tubes and opening a Reset switch through which a |08; I4, |24, etc. are biased olf when the switch negative potential is applied from thel battery Sv|02 'is in its left-hand closed position and are |09 to the control grids of the triodes -|02| |2 biased on when the switch S|02 is in its right- |22|32|l|2|52, etc. This standby condi- 20 hand closed position. p l Y tion is always established before the pulses rep- The various steps in the operation of the resenting the variable X are applied to the tercounter of Fig. 3 are indicated inthe following minal 25` of Fig. 1. v tabulationand are readily understood without Plate voltage for operating these various trigdetailed explanation. In this tabulation, theV ger circuits is applied between the terminals 25 frStrCOlurnn indates the Successive pulSes apmarked with a sign and ground; Grid'bias poplied to the terminal 25 for establishing in the tential is illustrated as derived from separate counter the representation of a given valueof batteries for each trigger circuit but obviously the variable; the second vto seventh Ycolumns-show may be derived from any other suitable source. whether current is beingconducted by the right- If the lower part of counter of Fig. 3 is assumed 30 hand side (R.)` or the left-hand sidev (L) `after to be the counter 26 of Fig. l, the terminals 25 of each of the applied pulses; the eighth column in- Fig. 3 correspond to the terminals 25 of Fig. 1. dicates the successive pulses applied to the ter The counters 26 and 21 of Fig. 1 are in effect the minal 25 for reducing the count inA the counter4V t lower order section and the higher order section section 26; and the ninth column shows the posi` of a single counter which is connected as indition of the switches S|0|Yand SI02.

Trig. oimuitoond. sut-Y Add Puls Y zalig Remarks N@ 1o1-1o2111-112121-122131-132141-142151-1s2 No;

R R R R R R Lv R R 4R `R R Y R L R `R,RR 1. L 1 `L R R YR R switches s101 `and R R Y L R R R S102 closed .to left L R L R yR 'for-adding pluses. R L L R R vR- .f L L L L R RV :..R R R R L R R L L L R R R 1 e e s e s s 'th s101 u.

Y vllgZ goscd to riglllit R L R .R R R 6 for subtracting L R Rv R VR R 7 Purlses' R R Y R R R R s iv L -L Li L L L 9 Switches S-l and, 1 R R R R R 'R S102 doseatothe 2...---- L R R R R lR left for adding,

".pulses.

cated by Fig. 3 and is provided with terminals In connection Y.with vthe above tabulationit 46" and 40' for applying the negative pulses by should be noted that the zero setting orfstandby which the counts of the two sections are reduced. ,D condition of the various triggercircuits is estab5 While the section 25 has been shown in Fig. 3 as m lished by closing and opening the Reset switch. including ve trigger circuits and only the rst This puts current conduction in the left hand tri-VA trigger circuit of the section 21 has been shown, ode of each'trigger circuit. With switches S|0| it will be understood that ve'ach section of. the and S|02-closed to the left so that the left hand counter will include a sufficient number of trigger transfer ltubes are conductive and the right hand circuits to handle all the required values of the transfer tubes are non-conductive, the eifect of variables. the rst counting pulse applied` toY thecounter Negative pulses are applied to theterminals 25 input terminal 25 is to transfer current conducas previously explained for establishing in the tion to the right-hand triode of each trigger circounter sections 26 and2l a representation of a cuit as indicated by the tabulation.

0 When a condition representative of the'given given value of one of the variables. The negative pulses through which current transfer is effected in the trigger circuits lll-I l2, I2 |-|22, I3 |-|32, etc. are derived from the various anodes through transfer tubes |05, I5, |26, etc. for addition of the pulsesapplied to the terminals 25'and value of the variable has been established bythe Y application of counting pulses tothe terminals 25, the switches Sli and-SW2 are Yclosed to the Y right biasingoif the transfer .106, ||,l'1,'etc..anc l" 15 biasing'onlthe transfer tubes |08, Ild'; t'c. :Under these conditions, the application of subtracting pulses from the oscillator -31 through the Shaper 45, the switches 46 and 46 .and the lead 46 to the input terminals of the trigger circuit E61 and 162 causes current conduction to be transferred in thetrigger circuits of the counter 26 as indicated by the second or subtracting section of the above tabulation. The operation of the counter 2l is similar to that of the counter 26 with the exception that the subtracting pulses are 'applied from the screen 18 through the conductor 46 to the input terminal oi the lowest order trigger circuit 151-152 of the counter 2l.

For the sake of simplicity, the count has not been made large enough to extend into the counter section 2'1. It is apparent, however, that whatever count is established in the count-er section 21 will be reduced by pulses applied to the lead 4S (Figs. 1 and 3) in exactly the same manner as the count in the counter section 26 is reduced by the application of pulses to the lead 46" (Figs. 1 and 3).

It will be observed that (1) the first adding pulse transfers current to the right-hand sides of all the trigger circuits and (2) the last subtracting pulse puts current in the left-hand sides of all the trigger circuits` The fact that only the last subtracting pulse puts current in the lefthand side of the highest order trigger circuit of the counter section 26 makes it possible to utilize the anode potential of the left-hand triode of the trigger circuit 141-142 to open the switch 46 and interrupt the supply of pulses from the oscillator 31 when the count of the counter section 26 is reduced to zero.

In like manner, the last subtracting pulse applied from the screen to the conductor 4S of the counter section 2'1 provides a control pulse by which the switch 46' is closed to transmit subtracting pulses from the oscillator 31v to the lead 46" of the counter section 26.

The details of the switches 46 and 46' are shown in Fig. 4. Each of these switches includes a trigger circuit ID3- 165 and a triode 1 13. The triode 113 is conductive when current is in the right-hand side of the trigger circuit 1133--165 and is non-conductive when current is in the lefthand side of this trigger circuit. This change in the conductivity of the triode 1 13 is the result of change in the voltage drop of a resistor 11'1 connected in the cathode lead of the triode 163 and is controlled by the application of negative pulses totheturn-on lead 164 and to the turn-off lead 1 16. Only when thetriode 113 is conductive are'pulses applied to the switch input lead 162 delivered at the switch output lead 163. As prev iously indicated, (l) a negative pulse is applied to the lead 164 by closing and opening'the switch 164 for shifting current conduction from the triode 103 to the triode 1135 so that pulses are applied from the input lead 162 through the triode 113 to the output lead 163 and (2) the last trigger circuit 141-142 has current conduction transferred to its left hand triode 141 only in response to the last subtracting pulse. When this occurs, a negative pulse is applied to the lead 116 and the switch of Fig. 4 is opened so that pulses are not transmitted between the leads 162 and 163. It is apparent that the application of a positive pulse through the lead 116 to the grid of the triode 195 can not aiTect the operation of this triode for the reason that it is conducting current while the switch of Fig. 4 is open.

The shaper 45 (Fig. 1) may be any one of the types usually utilized to convert an oscillator output to flat-topped pulses suitable for increasing the charge of the capacitor 48 by discrete steps. The constructional features of such Shapers are too well known to require detailed description.

The counter 23 in which a representation of a value of the function is established may be like the counter sections 26 and 2'1with the exception that the transfer `elements utilized for subtraction may be omitted.

In the operation of the computer of Fig. 1, a count representative of a given value of the variable is established in the counter sections 26 and 21 with switches 46 and 46 open'so that no impulses are transmitted through them.

When such count has been established, the switches S1111 and S102 (Fig. 3) are closed to the right and a switch 164 is closed and opened to apply to the turn-on terminal of the switch 46 a negative pulse whereby this switch is closed. Under these conditions, pulses are applied from the oscillator 31 through the Shaper 45, the switch 46 and the diode 41 to the capacitor 48. Each of these pulses increases the charge of the capacitor 48 by a predetermined amount so that the ray of the tube 11l is moved by discrete steps transversely of the conductors 18 of the screen 18.

Each time the ray strikes one of the conductors 18', a negative pulse is delivered through the lead 49 to the input terminal of the counter section 2'1 and the count .of this counter section is reduced by one count.

When the count of the counter section 2'1 has been reduced to zero, a negative pulse is applied to the turn-on lead of the switch 46 and pulses are applied both (l) to continue the step by step increase in the charge of the capacitor 43 and (2) to decrease the count of the counter section 26.

When the count of the counter section 26 has been reduced to zero, a negative pulse is applied through the conductor 116 to the turn-01T lead of the switch 46, thereby interrupting the application of impulses from the oscillator 31.

This leaves the ray of the tube 11 at, some point such as P from which it is returned along the horizontal line of Fig. 2 to its normal position by closing and opening the switch 48.

The switch 46 is opened by closing and opening a switch 165.

Each time the ray of the tube crosses one of the lines 44 of the target 22, a pulse isdelivered to the counter 23. The final count established in this counter represents the value of the desired function of the variable and may be observed on the indicator 24. As is well known to those skilled in the art, the indicator 24 may consist of a plurality of gaseous conduction lamps each of which is connected acrossv the anode resistor on the binary 1 side of a diierent trigger circuit of the counter 23.

The modification of Fig. 5 is similar in several respects to that of Fig. 1 but differs therefrom in the means by which the step by step movement of the cathode ray of the tube Il is effected. In this modification is also shown a screen 26 which is provided with accurately spaced horizontal wires 26' and forms a part of the computer of Fig. 1 when this computer is utilized to derive a function of more than one variable. The addition of this screen 26 of course requires the provision of a duplicate set of counters and switches as explained in connection with Fig. 1. lThisduplicate set of counters and switches is indicated in Fig. 5 by the reference numerals 34, 30, 32 and 42.

The modied means for controlling the step by step movement of the cathode ray includes (l) an amplier 39, a limiter 38, the screen I8 anda screen I9 for controlling the horizontal movement of the ray and (2) an amplifier 40, a limiter 4|, screen 29 and a screen 2| for controlling vertical movement of the ray.

How the amplier 39 functions in producing the step by step movement of the cathode ray will be understood from consideration of Fig. 6. In this figure, the electron gun corresponds to the electrodes I2 to I5 by which the ray of the tube II is produced. The ray itself is indicated by a broken line extending between the horizontal deflectors 29-29. One of the conductors of the screen I8 is represented by an area I8' and the space between such conductors is represented by an area |61. The amplifier 39 is shown as consisting of two stages |68 and |69 which are resistance coupled in a well known manner.

Impulses for moving the cathode ray are applied to the deflectors 29-29' through a lead |10. Impulses for arresting the movement of the ray are applied to the deectors 29-29 from the output of the amplifier 39 through a lead I 1|. The input potential of the amplifier 39 is derived from the area I8 through the limiter 38 in the case of the screen I8 (and directly from the conductors of the screen I9 as later explained).

When the ray tends to move onto the area I8', the input potential of the stage |68 is made more negative, the current of this stage is reduced, the input potential of the stage |69 is made `more positive, the current of this stage is increased and the potential of the deiiector 29 is made more negative, thereby moving the beam vtoward lthe area |61. When the ray tends to move onto the area |61 (corresponding to the space between the conductors I8), the input potential of the stage |68 is made more positive, the current of this stage is increased, the input potential of the stage |69 is made more negative, the current of this stage is decreased and a more positive potential is applied to the deflector 29. In this manner the beam is maintained in a position of equilibrium where it is divided between the areas I8 and |61. The ray is stabilized in this position until there is applied through the lead |10 to the deector 29 a pulse of suicient amplitude to deect it to, or a little beyond, the next conductor I8' where the ray stabil'zing action explained above is repeated. In this way the beam is moved by discrete steps across the screen I8 and also across the screens I9, 29 and 2|.

As indicated above, the conductors I8 of the screen I8 are accurately spaced. The conductors of the screen I9 are a predetermined multiple of those of the screen I8 and are so arranged that each conductor of the screen I 8 is alined with one of the conductors of the screen I9. The accuracy of the spacing between the conductors of the screen I9 need not be exceptionally high for the reason that the incremental deflection of the ray is corrected or compensated each time the ray strikes one of the accurately spaced conductors of the screen I8. Otherwise stated, relatively accurate interpolation between Values defined by the accurately and widely spaced conductorsof the screen |8 is provided. While the conductors of the screen I9 rare a predetermined multiple of the conductorsof the screen I8, as stated above, it is apparent that this multiple can have any desired value depending on the required accuracy of the interpolation. The Whole function of the conductors of the ne screen I9 is to so control the cathode ray that it Y l0 moves step by step (one step for eachrpulserapplied to the deflector 29') from the left hand side of the target 22. In this step by step'rnovement it (l) crosses a number of vthe conductors I8 which is determined by the count established in the coarse counter 21 and (2) an additional number of the conductors of the -fine screen I9 which is determined by the countestablished in the fine counter 26. From this it follows that the coarse counter should have as many trigger circuits as there are conductors inthe coarse screen I8 and the ne counter should haveas many trigger circuits as the number of iine screen conductors for each of the coarse screen conductors.

How many of the conductors I8 are crossed by the ray is determined by the count established in the coarse Vcounter 21. How many conductors o f the screen I9 are crossed by the ray after the last conductor I8' (determined bythe count es- Y tablished in the coarse counter) is crossed is determined by the count established in the fine counter 26. y

The different countsestablishel in theV coarse and fine counters (l) represent diierent values of the variable X, (2) may have any value vfrom a count of one on the i'lne counter 26 to a countA explained, and the cathode ray vis .movedinto 1` alignment with the rst conductors of thecoarse and ne screenswhere it is stabilized as previously explained. If the coarse counter 21 is in a condition representative of one input pulse and the iine counter 26'is in a condition representative of three input pulses, the rst pulse from the oscillator 3| moves thecathode ray to the first conductors of the two screens thu's'restoring the counter 21 to its standby condition and closingA the switch 46' so thatsuccessive pulses are ap" plied through it to the input terminal25 o f the ne counter 26. The next three input pulses Ife-V store the fine counterY 26 to its standby 'condition thus opening the switch i6 and leaving the Aray stabilized at the fourth conductorofthe ne screen. This position of the ray is representative of one'count of thejcoarse counter 21'plus some fraction of this count. The value ofthis fraction, of c0urse,is dependent on ,the'relation'betw'een the numbers of conductors of the' two screens.

What has been said Withrespect to the spacing and arrangement of the conductors of the screens I8 and I9y is also true of the screens 29 and 2| which diier from the screens I9 and I9" only in that their conductors are arranged horizontally instead of vertically. Y

The limiters 38 and 9|' each function (l) to equalize `the amplitude of the pulses applied from the coarse and ne screens to the inputs ofthe amplifiers and (2) ^toiisolate the fine screensfrom the coarsejscreen; and'Y the counter to whichit is connected. v Thusthe limiter 38 serves to make the amplitude of the pulses -appliedv from; the coarse screen 38 toV the amplifier 39 equalfto the amplitudo the pulses applied to thisv amplifier from the ne screen I9 and to isolate the screen'. I9 from the screen I8 and counter 21`ffr'om the screen I9.

The switches 32, 42, 46 and 46' are of the same type as that illustrated by `Figfl. With. these alias-,1077

switches open, a count representative of a given value of the variable X is established in the counters 25 and 2 by applying a predetermined number of pulses to the terminals 25 as explained in connection with Figs. 1 to 4. A count representative of the variable Y is similarly established the counters 29 and 39 by applying a predetermined number of pulses to the terminal 33.

Reduction of the counts of the counters 26-21 is initiated by closing and opening the switch {64 as explained in connection with Fig. l. Reduction of the counts oi the counters 29 and 30 is initiated similarly by closing and opening the switch |64. If the horizontal and vertical deflecting systems are operated simultaneously, `,such operation must be preceded by closing and opening the switches 84 and 164 simultaneously or otherwise so that pulses from the oscillator 3| wfill be transmitted through them to the deiietors 28 and 29 respectively. These deflecting systems also may be operated separately by closing the switches 64 and H54 at diiferent times.

As these counts are reduced, the ray of the tube 'l I is moved from its normal position at the lower left-hand corner of the target 22 horizontally and vertically so that it reaches the point P when all the counts have been reduced to zero. 1n traveling to the point P, the ray crosses a nurnber of -lines 44 and produces a number of pulses such as to establish in the counter 23 a representation of the value of the function corresponding to the given values of the variables X and Y.

The manner in which this result is achieved has been indicated in connection with Figs. 1 to 4, Remembering that the assembly 34-30- 3;'2-42 operates in the same way as the assembly 2531-21-445-4352 it is now to be explained by following through the operation of the circuits b y which horizontal movement of the ray is effected.

.Assuming that a count representative of a given value `of the variable X has been established in the counters 26 and 2 and that the switches 46 and 4,5 are open, the rst step in the operation is to'clolse and open the switch 64. This closes the switch 46.

When the switch 4S is closed, pulses from the oscillator 3| are applied through it to the horizontal de iiector 29. The rst of these pulses moves the ray to, or a little beyond, the rst conductor of the fine screen I9 where it is stabilized'at the edge of this conductor as explained in connection with Fig. 6. The second pulse moves the ray to the next conductor of the screen I9 where it is similarly stabilized. This action is repeated for each successive pulse until the ray strikes a conductor of the screen I8.

When the ray strikes the first conductor of the screen I8, a negative pulse is applied from this conductor (l) through the limiter 38 and amplifier 39 for stabilizing the ray at the edge of this nrst conductor, and (2) to the coarse counter section 2 for reducing its count -by one.

Successive pulses applied from the oscillator 3l continue the action outlined above until the count of the counter 21 is reduced to Zero.

When the count of the counter 21 is reduced to zero, there is delivered from this counter a negative pulse by which the switch 46 is opened and the switch 46 is closed.

When the switch 46 is closed, pulses are applied through it from the oscillator 3l (1) to the terminal 25 of the ne counter 26 and (2) to 12 the defle'ctor 29, thereby reducing the count of this counter to zero'.

When the count of the counter 2S is reduced to zero, the ray is at the edge of a conductor of the screen I9- which is located somewhere between the conductors of the screen I8 and a pulse is transmitted from the counter 26 through a capacitor |12 for opening the switch 46 so that the application of pulses from the oscillator 3| is interrupted.

The operation of the vertical control system is the same as that of the horizontal control system.

As the result of these two deflections there is established in the counter 23 a representation of a value of the function ofthe variables X and Y, this value of course being determined by the selected values of these two variables.

It is thus seen that the computer of Fig. 1 is readily adapted to derive the function of more than one variable merely by the addition of (1) the screen 20 of Fig. 5 and (2) a vertical control system which is the duplicate of the horizontal control system of Fig. 1. These and similar changes are clearlywithin the scope of the present invention. The outstanding characteristic of the invention is of course the accurately spaced conductors of the screens I8 and 2D through which any irregularities in the step by step movement of the ray are connected each time the ray strikes one of 'these accurately spaced conductors.

I claim as my invention:

l. The combination of input terminals to which may be applied a first series of pulses representative of a given value of a variable, means operable in response tosaid first series of pulses for establishing counts of the higher order digits and the lower order digits of a number representative of said vgiven. value of a variable, a cathode ray tube provided with arcoarse screen havin g accurately spaced conductors, with a ne screen having less accurately spaced conductors, with a target electrode having secondary electron emissive lines arranged and spaced in accordance with a desired function of said variable and with ray defiectors, means for applying a second series of electrical pulses to said deectors for moving said ray from one to another of said conductors, means for stabilizing said ray at each of said conductors, means responsive to impact of said ray on each c onductor of said coarse screen for reducing said higher order count by one, and means responsive to each successive pulse of said second series of pulses for reducing said lower order count by one and for deflecting said ray to successive fine screen conductors after said higher order count is eliminated.

2. The combination of input terminals to which may be applied a first series of pulses representative of a given value of a variable, means operable in response to said rst series of pulses for establishing counts of the higher order digits and the lower order digits of a number representative of said given value of a variable, a cathode ray tube provided with a coarse screen having ac- -curately spaced conductors, with a iine screen having less accurately spaced conductors, with a target electrode having secondary electron emissive lines arranged and spaced in accordance with a desired function of said variable and with ray denectors, means for applying a second series of electrical pulses to said deectors for moving said ray from one to another of said conductors, means for stabilizing .said ray at each of said conductors, means `responsive to impact of said ray on each conductor of said coarse screen; for reducing said higher order count by one, means responsive to each successive pulse ofsaid second series of pulses for reducing said lower order count by one and for delecting said ray to successive fine screen conductors after said higher order count is eliminated, and means responsive to passage of said ray over said secondary electron emissive lines for establishing a count representative of the desired function of said variable. f'

3. An electronic computer for deriving a predetermined function of two variables which includes a cathode ray tube having ray generating means, ray deflecting means, electrode pairs each including a ne and coarse screen and a target electrode having ray responsive means `'spaced thereon in accordance with said function, means including a first pulse accumulator device respon# sive to one of said variables for deiiecting said ray of said tube across one of said pairs and along one coordinate of said target electrode, means 'including a second pulse accumulator device' responsive to the other of said'variables for deecting said ray of said tube across the other of said pairs and along a second coordinate of said target electrode, means including said rst and said second pulse accumulator devices responsive to said deiiections of said ray across said pairs for interpolating in terms of both of said variables for values of said variables intermediate predetermined discrete deiiection steps, and means for deriving voltage pulses from said target electrode of a number representative of the interpolated value of said function of said variables.

4. An electronic computer for deriving a predetermined function of two variables which includes a cathode ray tube having ray'generating means, ray deflecting means, electrode pairs each including a iine and coarse screen and Va, target electrode having ray responsive means' spaced thereon in accordance with said (function, means including a first pulse accumulator device responsive to one of said variables for deflecting said ray of said tube by discrete steps across one of said pairs and along one coordinate of Said target electrode, means including a second pulse accumulator device responsive to the other oisaid variables for defiecting said ray of said tube by discrete steps across the other of said pairs and along a second coordinate of said target.,elec, trode, means including said first and said second pulse accumulator devices responsive to said discrete deflections of said ray across said pairs for interpolating in terms of both of said variables for values of said variables intermediate predetermined ones of said discrete deflection steps, and means for deriving voltage pulses from said target electrode of a number representative of the interpolated value of said function of said variables.

5. An electronic computer for deriving a predetermined function of two variables which includes a cathode ray tube having ray generating means, ray deecting means, pairs of screen electrodes each including Aa screen having accurately spaced openings and a screen having less' 'ac'- curately spaced openings and a` target electrodehaving ray responsive means spaced thereon in accordance with said function, means including a rst pulse accumulator device responsive to one. of said variables for deecting said ray of said tube by discrete steps across one of said pairs and along one coordinate of said target electrode,kmeans'includingra second pulse acrzumulai tor device responsive to the other of' said var.

iables for deiiecting said ray of said tube by dis-V crete steps across the other of saidpairs and along a second coordinate of said target electrode, whereby both of said variables are interpolated for values of said variables intermediate predetermined ones of said discrete deection steps, means for deriving voltage pulses from said target` electrode of ay number representative of the interpolated value of said function of said variables, and means responsive to said derived pulses by indicating the value of saidvfunction. y

le. The Vcombination -of a cathode ray device including ray. deiiecting means and a pair of screen `electrodes one of which has relatively closely spaced conductors-andthe other of Ywhich has relatively Widely spaced ,conductors each aligned with a diierent one of said closely spaced conductors, means for applying pulses tosaiddefleeting means, and means connected-between said screen electrodes and said delectingfmeansfor stabilizing saidl ray at successive kones of 'said sive ones of said pulses.

7. The combination of a including ray deflectingV means and a pair of screen electrodes one of which has relatively closely spaced conductors and the other of which has relatively widely spaced conductors each aligned with a different one of'said closely spaced conductors, means for applying pulses lto said de iiecting means, means Vconnected betweenf said screenvelectrodes and said deecting means for stabilizingsaid rayl at successive ones of saidy closelyjspaced conductors in` response to succes-V sive onesgofsaid pulses, and counter means connected to said widely spaced conductor screen for 40 predetermining the number of said .widely spaced conductors at which said ray is stabilized.

8; The combination of a` cathodeY ray device including Vray'A deflecting means? and.. a pair .of

screenV electrodes one of whichv has'relatively closely'ospaced conductors and the'other of which has relatively Widely Vspaced conductorsl each aligned with'a different one of said'closely spaced conductors, meansfor applying pulses to said deflecting means, means connected between said screen electrodes and said deilecting means for stabilizing said ray at successive Vones of said closely spaced conductors in response to successive ones of said pulses, counter means connected to said ywidely spaced conductor screen 4 for pre- 55 `determining the number of said 'widely spaced conductors at which said ray is stabilized, and

means operable in response to a predetermined condition of said counter means for predeter-f` mining the number of said c 'osely spaced convspaced conductors. i i Y 9. The combination of pairs of input'terminals to the rst off which pairsmay be applied a iirst series of pulses representative of al given value of a variable, means lo perablein response to said Iirst seriesfofpulses for establishing counts of the*higherjorderdigitsand lower Vorder digits of a numberrepresentatiye 'ofV said vgiven value of a Vvaria1 `le, means Vfor applyingasec'ond series sponsivek to said'secondseries ofpulses'V forre;

ducing said higher order count by one in response to each. successive group of a predetermined plurality of said second seriesA of pulses, and means closely spaced conductors in response to sucoescathode ray device ductors at which said ray is stabilized after it is stabilized at the last ofsaid number offwidely is responsive to the elimination of said higher order count for reducing said lower order :count by one in response to each successive one of said second series of pulses.

10. The combination of pairs of input terminals to the first of which pairs may be applied a iirst series of pulses representative of a given Value of a variable, means operable in response to said rst series of pulses for establishing counts of the higher order digits and lower order digits of a number representative of said given value of a Variable, means for applying a second series of pulses to the second of said pairs, means responsive to said second series of pulses for reducing said higher order count by one in response to each successive group of a predetermined plural--M ity of said second series of pulses, means responsive to the elimination of said higher order count for reducing said lower order count by one in response to each successive one of said second series of pulses, and means responsive to the elimination of said lower order count for interrupting the supply of said second series of pulses.

11. The combination of pairs of input'terminals to the rst of which pairs may be applied a first series of pulses representative of a given value of a variable, means operable in response to said first series of pulses for establishing counts of the higher order digits and lower order digits of a number representative of said given value of a variable, means for applying a second series of pulses to the second of said pairs, a cathode ray tube including a screen having accurately spaced conductors, means including said screen for reducing said higher order count by one in response to each successive group of a predetermined plurality of said second series of pulses, and means responsive to the elimination of said higher order count for reducing said lower order count by one in response to each successive one of said second series of pulses.

12. The combination of pairs of. input terminals to the: first of which pairs may be applied a rst series of pulses representative of a given value of a variable, means operable in response to said: first series of pulses forY establishing counts of theV higher order digits and lower'order digits of a number representative of said given value ofa Variable, means for applying a second series of pulses to the second of said pairs, a r

capacitor connected to be charged by said second series of pulses, a cathode ray tube including a ray deiiector connected to said capacitor and a screen havingy accurately spaced conductors; means including said screen connected to said second pair of input terminals for reducing said higher order count by one in response to each successive group of a predetermined plurality of said second series of pulses, and means responsive to the elimination of said higher order count for reducing said lower order count by one in response to each successive one of said second series of pulses.

13. In a computer for deriving'a predetermined function of two variables, the combination of a cathode ray tube having (1) ray generating means (2) ray deflectors, (3) electrode-pairs each including coarse and fine screens and (4)a tari get electrode having ray responsive nieansspaced thereon in accordance with said function, means including a rst pulse accumulator vdevice connected to the rst of said coarse screens andresponsive tov theI first of said variables for deiiecting 4the .ray of said tube by discrete steps across the 'r'st of said pairs oi screens and along a first coordinate of said target electrode, means including a rst D.--C. amplifier connected between said first coarse screen and a first of said deflectors for stabilizing said ra'y at the end. of each step along said first coordinate, means including a second pulse accumulator deviceconnected to the second of said coarse screens and Aresponsive to the second of said variables for defleoting the ray of said tube across the second of said pairs of screens and along a second coordinate of Asaid target electrode, means including a secondlD.-C. amplifier connected Ybetween said second coarse screen and the second ofsaid deflectors for stabilizing said ray at the endl of each step along the second of said coordinates, and means includ-ing said first 'and second accumulator devices responsive to said discrete deflections of said ray across said pairs of screens for interpolating in terms of both of said variables for values of said variables which are ygreater than those represented by said discrete deflection steps.

14. linf a computer for deriving a predetermined function fof two variables, the combination of a cathode ray tube having (l) ray generating means (2) ray deiiectors, (3) electrode pairs each including coarse and fine screens and (4) a target electrode having ray responsive means spaced thereon in accordance with said function, means including a first pulse accumulatorv device connected to the first ofsaid coarse screens and responsive to the first of said variables for deflec'tng the ray o'f saidtube by discrete steps across the first of said pairs of screens and along a first coordinate of said target electrode, means .including a rst D1-C. amplin'er connected between said first coarse screen and a first of said deiiectors for stabilizing said ray at the en'd of said step Aalong said rst coordinate, means including a second` pulse accumulator device'f, connected to the second oi ysaid coarse screens Aaridresponsive to theV second of Ysaid variables' for deflecting the ray of said tube across'v the second of ,said pairs of screens and along a second coordinate of said target electrode, means including a second D.-'C. amplifier connected' between said second coarse screen and the second of saiddelectors for stabilizing said ray at the end of each step along the second of vsaid coordinates, means including said rst and second accumulator devices responsive to said discrete deflections of said ray across said pairs oi" screens for interpolating in terms of Vboth ol. said variables for values of saidvariables` which are greater thanthose represented by said discrete deflection steps",v and meansA for deriving from said target electrodevvoltage pulses of a number representative of the interpolated value of said function of said variable.

GEORGE A. MORTON.

REEERENGQS CITED The following references are of record Vin the le of this patent: f i

UNITED STATES PATENTS Mortoneet al. i f Aug. 10, 1948 

